Looks like a HUGE limitation...
So you want to develop native iOS apps, on Windows with a remote Mac compiler while the device is connected to a different network? This is quite an edge case.
1. Why don't you connect the ESP8266 to the network that the PC is connected to?
2. You can compile your app in release mode and it will run without being connected to the IDE.
3. A bit more tricky, you can compile your app in debug mode and start it. Then connect the PC to the ESP8266 network and run the app again. It will not need a full compilation so the hosted builder will not be needed.